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  <title>为迭代器中每个元素调用一个用户自定义函数</title>
 </head>
 <body class="docs"><div id="layout">
  <div id="layout-content"><div id="function.iterator-apply" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">iterator_apply</h1>
  <p class="verinfo">(PHP 5 &gt;= 5.1.0, PHP 7)</p><p class="refpurpose"><span class="refname">iterator_apply</span> &mdash; <span class="dc-title">为迭代器中每个元素调用一个用户自定义函数</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.iterator-apply-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>iterator_apply</strong></span>
    ( <span class="methodparam"><span class="type"><a href="class.traversable.html" class="type Traversable">Traversable</a></span> <code class="parameter">$iterator</code></span>
   , <span class="methodparam"><span class="type"><a href="language.types.callable.html" class="type callable">callable</a></span> <code class="parameter">$function</code></span>
   [, <span class="methodparam"><span class="type">array</span> <code class="parameter">$args</code></span>
  ] ) : <span class="type">int</span></div>

  <p class="para rdfs-comment">
   循环迭代每个元素时调用某一回调函数。
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.iterator-apply-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<code class="parameter">iterator</code></dt>

     <dd>

      <p class="para">
       需要循环迭代的类对象。
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">function</code></dt>

     <dd>

      <p class="para">
       迭代到每个元素时的调用的回调函数。
       <blockquote class="note"><p><strong class="note">Note</strong>: 
        <span class="simpara">
         为了遍历 <code class="parameter">iterator</code> 这个函数必须返回 <strong><code>TRUE</code></strong>。
        </span>
       </p></blockquote>
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">args</code></dt>

     <dd>

      <p class="para">
       传递到回调函数的参数。
      </p>
     </dd>

    
   </dl>

  </p>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.iterator-apply-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   返回已迭代的元素个数。
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.iterator-apply-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-4716">
    <p><strong>Example #1 <span class="function"><strong>iterator_apply()</strong></span> example</strong></p>
    <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">function&nbsp;</span><span style="color: #0000BB">print_caps</span><span style="color: #007700">(</span><span style="color: #0000BB">Iterator&nbsp;$iterator</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #0000BB">strtoupper</span><span style="color: #007700">(</span><span style="color: #0000BB">$iterator</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">current</span><span style="color: #007700">())&nbsp;.&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">TRUE</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$it&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">ArrayIterator</span><span style="color: #007700">(array(</span><span style="color: #DD0000">"Apples"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"Bananas"</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"Cherries"</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">iterator_apply</span><span style="color: #007700">(</span><span style="color: #0000BB">$it</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">"print_caps"</span><span style="color: #007700">,&nbsp;array(</span><span style="color: #0000BB">$it</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
    </div>

    <div class="example-contents"><p>以上例程会输出：</p></div>
    <div class="example-contents screen">
<div class="cdata"><pre>
APPLES
BANANAS
CHERRIES
</pre></div>
    </div>
   </div>
  </p>
 </div>




 <div class="refsect1 seealso" id="refsect1-function.iterator-apply-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="array_walk.html" class="function" rel="rdfs-seeAlso">array_walk()</a> - 使用用户自定义函数对数组中的每个元素做回调处理</span></li>
   </ul>
  </p>
 </div>


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